Archive | 2019
Two-dimensional mesoporous g-C3N4 nanosheets coupled with nonstoichiometric Zn-Cu-In-S nanocrystals for enhancing activity of photocatalytic water splitting
Abstract
Graphitic carbon nitride (g-C3N4) is the most stable allotrope of carbon nitride with a conjugated, two-dimensional polymer of s-triazine, which is considered as a promising photocatalyst in sustainable chemistry. The low surface area and quantum efficiency and fast electron-hole recombination of g-C3N4 restrict its practical application. The formation of two-dimensional mesoporous structure and the construction of proper semiconductor composites are two approaches to promote the effective separation of photogenerated exciton and reduce the charge transfer resistance, which is beneficial to restrain the recombination of exciton and improve photocatalytic hydrogen performance. In this work, two-dimensional mesoporous g-C3N4 nanosheets (MCNS) coupled with nonstoichiometric Zn-Cu-In-S (ZCIS) nanocrystals were synthesized by a hydrothermal method. The constructed ZCIS/MCNS composites possessed highly photocatalytic hydrogen evolution performance under visible light irradiation without any noble metal cocatalysts. The EIS spectra and transient photocurrent responses corroborated ZCIS/MCNS had higher separation and transportation efficiency of photogenerated electron and hole. The incorporation of ZCIS into MCNS reduced the charge transfer resistance and enhanced the charge transfer efficiency. As the result, the photocatalytic hydrogen evolution rate of ZCIS/MCNS was higher than those of pure ZCIS and MCNS. 10-0.2ZCIS/MCNS showed a highest H2 production rate of 12.3 μmol h−1 over 100 mg photocatalyst without cocatalysts. This work supplied a feasible strategy to construct ZCIS/MCNS composites for the exploitation of solar energy.